Why it matters
Opt-out handling is non-negotiable. Failing to honor STOP requests is a per-message TCPA violation. Beyond legal exposure, ignored opt-outs drive carrier complaints — which destroy sender reputation faster than any other signal.
How it affects messaging performance
Properly honored opt-outs protect deliverability and reputation. The suppression list must be enforced across every campaign, automation, and integration — not just the channel where the opt-out happened.